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RAFT聚合制备PMPS-b-PNIPAM嵌段共聚物及温敏性纳米粒子 总被引:1,自引:0,他引:1
利用可逆加成-断裂链转移(RAFT)活性自由基聚合合成了一系列分子量可控、分子量分布窄的甲基丙烯酸-3-三甲氧基硅丙酯(MPS)和N-异丙基丙烯酰胺(NIPAM)的嵌段共聚物,在水溶液中分散制备温敏性的含硅纳米粒子。保持疏水链段PMPS的长度恒定,改变亲水链段PNIPAM的长度,在不同pH的水溶液中进行实验,研究亲水链段长度、pH对聚合物的临界聚集浓度、纳米粒子的尺寸和形貌以及温度变化过程中的相分离行为的影响,得到尺寸较小、溶液稳定的温度响应性含硅纳米粒子,同时具有有机物和无机物的优良特点,在生物医学、化学催化、纳米反应器、染料涂料等多领域具有广泛的应用前景。 相似文献
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无机纳米粒子增韧聚丙烯及其机理研究 总被引:4,自引:0,他引:4
综述了无机纳米粒子增韧聚丙烯的最新研究进展,阐述了不同纳米粒子对聚丙烯增韧效果的影响,介绍了无机纳米粒子的物理化学作用增韧机理和微裂纹化增韧机理。并对增韧改性聚丙烯的发展前景进行展望。 相似文献
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用乳液聚合法制备了纳米TiO2/甲基丙烯酸甲酯-丙烯酸丁酯-甲基丙烯酸共聚物[TiO2/P(MMA-BA-MAA)]复合粒子。考察了乳化剂的浓度、单体的用量比对复合粒子形貌的影响。系统研究了乳化剂浓度、引发剂用量、单体用量比、共乳化剂浓度、反应温度对TiO2/P(MMA-BA-MAA)复合粒子包覆反应动力学影响。用TEM、FTIR及TG分析等证实P(MMA-BA-MAA)包覆在TiO2表面形成表面光滑、分散性好的球形核 壳复合粒子。根据动力学实验结果,求出整个乳液聚合包覆反应的反应速率方程,反应的表观活化能为163.0 kJ.mol-1。推测可能的包覆反应机理应为无机纳米TiO2表面吸附乳化剂分子形成所谓的TiO2/surfactant胶束成核或均相凝聚成核。TG结果显示,复合粒子的热稳定性高于相同条件下得到的共聚物的稳定性。ζ电位、接触角实验表明,与纳米TiO2相比,复合粒子亲水性能下降、亲油性能提高。 相似文献
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用乳液聚合法制备了纳米TiO2/甲基丙烯酸甲酯-丙烯酸丁酯-甲基丙烯酸共聚物[TiO2/P(MMA-BA-MAA)]复合粒子。考察了乳化剂的浓度、单体的用量比对复合粒子形貌的影响。系统研究了乳化剂浓度、引发剂用量、单体用量比、共乳化剂浓度、反应温度对TiO2/P(MMA-BA-MAA)复合粒子包覆反应动力学影响。用TEM、FTIR及TG分析等证实P(MMA-BA-MAA)包覆在TiO2表面形成表面光滑、分散性好的球形核 壳复合粒子。根据动力学实验结果,求出整个乳液聚合包覆反应的反应速率方程,反应的表观活化能为163.0 kJ.mol-1。推测可能的包覆反应机理应为无机纳米TiO2表面吸附乳化剂分子形成所谓的TiO2/surfactant胶束成核或均相凝聚成核。TG结果显示,复合粒子的热稳定性高于相同条件下得到的共聚物的稳定性。ζ电位、接触角实验表明,与纳米TiO2相比,复合粒子亲水性能下降、亲油性能提高。 相似文献
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纳米材料具有诸多优良特性,使其具有物理性质与常规块体材料不同,被誉为本世纪最有前途的材料。纳米氧化铜具有低熔融温度、低分解温度和高热释放已经成为可用于亚稳态含能复合材料中的比较理想的氧化剂材料。以PEG为模板,用CuCl2·2H2O和NaOH为原料,通过溶液反应制备CuO纳米粒子。分别讨论了反应物配比、PEG的分子量、PEG用量对产物形貌的影响,以得到制备CuO纳米粒子的最佳实验条件。 相似文献
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阻燃PTT共聚酯的制备及性能研究 总被引:1,自引:0,他引:1
采用直接酯化-缩聚工艺,在酯化后加入磷系阻燃剂2-羧乙基苯基次膦酸(CEPPA)与1,3-丙二醇(PDO)的酯化溶液(CEPPA-PDO),制得阻燃聚对苯二甲酸丙二醇共聚酯(FR-PTT)。通过FT-IR、DSC、TG、SEM以及垂直燃烧法对FR-PTT的结构及性能进行表征。结果表明:阻燃剂CEPPA可能是以共聚的方式接入到大分子链中,并且随着磷含量的增加,FR-PTT的Tc上升,而Tm呈下降趋势,同时FR-PTT在高温处理后成炭性良好,阻燃级别达到FV-0级。 相似文献
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通过将聚氯乙烯(PVC)氯化原位接枝共聚含氟单体生成氯化聚氯乙烯接枝偏氟乙烯(CPVC-g-VDF),当配比为VDF占CPVC-g-VDF量的4%时,接枝聚合的效果最好,所得接枝聚合物的综合性能优于聚氯乙烯. 相似文献
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Tsung-Ming Chao Shinn-Jen Chang Cha-Wen Chang Chia-Chen Li 《Journal of surfactants and detergents》2020,23(4):841-851
Silver (Ag) nanoparticle has extremely high surface energy and it is difficult to find an efficient dispersant to prevent its agglomeration in suspensions. A new brush copolymer, succinic anhydride modified epoxy-amine poly[(propylene oxide)-co-(ethylene oxide)]-grafted polymer (EPOA), which can efficiently disperse concentrated aqueous suspensions of Ag nanoparticles is revealed. The dispersion efficiency of EPOA for the dispersion of a 60 nm-Ag nanoparticles in aqueous suspension is studied by measuring its sedimentation and rheological behavior, and the results are compared with those of a commercially available dispersant, ammonium poly(acrylic acid) (PAA-NH4). Interactions between the dispersants and the Ag nanoparticles are characterized by zeta potential and adsorption analyses. Theoretical calculations are conducted to clarify the adsorption and the dominant dispersion stabilization mechanisms of the dispersants. Compared with PAA-NH4, EPOA obtains a higher stable suspension of Ag nanoparticles with less significant sedimentation over 1 month. The dispersion homogeneity of the suspension remains excellent even at an extremely high solid loading of 30–40 wt%. According to adsorption analysis, it is suggested that both EPOA and PAA-NH4 adsorb via single-point attachment through the carboxyl group on the Ag surface. Based on theoretical calculations, the Ag nanoparticles are better stabilized by EPOA via an electrosteric dispersion mechanism. 相似文献
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《大分子材料与工程》2017,302(10)
Hybrid organic/inorganic thin film nanocomposites based on poly(styrene)‐b‐poly(butadiene)‐b‐poly(methyl methacrylate) triblock copolymer and silver nanoparticles are prepared and characterized. In order to improve the compatibility of nanoparticles with the polymeric matrix, their surface is modified with dodecanethiol surfactant, which enables a good dispersion of nanoparticles through the triblock copolymer, without the formation of aggregates. By atomic force microscopy (AFM), the dispersion level of nanoparticles is analyzed, together with their effect on the thin film surface morphology, for nanocomposites up to 15 wt% of nanoparticles. Dielectric properties of nanocomposites are studied by dielectric relaxation spectroscopy (DRS), analyzing the effect of nanoparticles on dielectric properties. Even if conductivity and permittivity of composites increase with nanoparticle content, percolation threshold is found to be at around 15% in volume. Morphologically analyzed nanocomposites are, in this way, below the threshold. 相似文献
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以正硅酸乙酯(C8H20O4Si),硝酸铝(Al(NO3)3·9H2O)为主要原料,氨水调节pH值,通过溶胶凝胶法制备出酸碱条件下纯相莫来石粉体.通过热分析得知粉体在升温过程中吸热、放热和晶相转换过程;通过XRD研究了凝胶在热处理过程中的结晶变化;通过红外吸收光谱测定了粉体中Si-O-Al键的存在和变化;通过环境扫描电子显微镜测定研究了莫来石粉末的表面特性.最终得出凝胶转变至莫来石的相变过程:酸碱条件下莫来石的生成过程都经历了由无定形铝和无定形硅转变为硅铝尖晶石再到莫来石的过程;在碱性条件下,莫来石开始转变温度低于酸性;同时生成的莫来石中,碱性条件比酸性条件粒度小. 相似文献
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嗜水气单胞菌胞内聚3-羟基丁酸-3-羟基己酸酯(PHBHHx)提取方法的研究 总被引:1,自引:0,他引:1
以嗜水气单胞菌利用月桂酸发酵生产PHBHHx,比较多种溶剂对提取率和产品质量的影响,建立了嗜水气单胞菌胞内提取PHBHHx的新方法。本方法使用湿细胞提取,节省干燥细胞的能耗,仲丁醇无异味、毒性小、价格低廉,而且可以循环多次利用、对相对分子质量影响小,解决了工业生产上能耗高,生产成本高,溶剂回收难,安全隐患多,提取率不高、产品质量低等问题。用仲丁醇作溶剂,预处理细胞提取率提高13%,相对分子质量达83万,提取率达78%,产品纯度达99%以上。 相似文献
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采用顶空气相色谱法,系统研究了丙烯腈共聚制品生产过程中工艺参数的调整对丙烯腈单体残留量的影响。分别对原料预热温度、机筒温度、注射压力进行了优化和选择。结果表明:对于ABS和AS原料,都选择80℃的预热温度,并分别选择(260、260、250、230)℃、(230、230、220、200)℃的机筒温度组合以及低压、高压的注射压力为最优工艺参数,丙烯腈共聚制品中的丙烯腈单体残留量与对应的生产原料相比,分别下降了5.31%~15.1%,而在其他工艺条件下生产的丙烯腈共聚制品,其丙烯腈单体残留量下降不明显,甚至大部分呈上升趋势。 相似文献
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Ling Zhong Changling Zhou Rongsheng Che 《Polymer-Plastics Technology and Engineering》2013,52(15):1515-1520
The functional acrylate monomer (FAM) containing an amino group was synthesized by using glycidyl methacrylate (GMA) and ammonia. FAM was then copolymerized with Vinyl acetate and other acrylate monomers by emulsion copolymerization. The cross-linkable latex was obtained by adding a set content of glutaraldehyde to the earlier copolymer emulsion. The FT-IR results show that the cross-linking reaction between amino and aldehyde groups is detected during the curing process of copolymer. The glass transition temperature (Tg) of the copolymer can be evidently increased from ?16.2 to ?8.7°C as the FAM alters from 0 to 10%. T-peel strength of the polyethylene-polyethylene (PE-PE) packaging films laminated by products was studied. The results show peel strength dramatically increases with the cross-linking density at room temperature, and still reaches 2.5 N·15 mm?1 even at 60°C, which can satisfy the application requirement enough. 相似文献